The Freshwater Balance of the Adriatic Sea: A Sensitivity Study

The Adriatic Sea is a narrow semi-enclosed basin with considerable freshwater inflow, connected to the saltier Mediterranean Sea through a narrow strait. The northern and central parts of the basin are characterized by a shallow shelf, while the southern part features a pit exceeding 1,200 m in depth. We conducted a series of modeling experiments over a 16-year period (2000-2015) using different runoff configurations and different sources of atmospheric forcing to investigate the sensitivity of the Adriatic Sea circulation and hydrology to freshwater balance and heat loss. Our results show that the shelf salinity and the salinity of the surface layers in the southern Adriatic are part of a self-amplifying loop involving dense water formation, water exchange with the Mediterranean Sea, and salty water intrusions to the shelf. Therefore, the characteristics of the basin and the water circulation are highly sensitive to the freshwater budget and heat losses. River discharge is subject to large interannual variations and is poorly known for many of the Adriatic freshwater sources. To improve the accuracy of the freshwater budget, we created a new climatology for three Albanian rivers and modulated the monthly climatological discharge in accordance with the rivers Po and Isonzo (Soca). Evaporation, precipitation, and heat losses vary strongly among the available atmospheric reanalyses and we show that the choice of atmospheric forcing has a substantial impact on the hydrology and circulation of the Adriatic Sea.

Automated summary

This study investigates the sensitivity of circulation and hydrology in the Adriatic Sea to freshwater balance and heat loss through a series of modeling experiments. The results show that the salinity in the shelf and surface waters of the southern Adriatic are part of a self-amplifying loop involving water exchange and density formation. Furthermore, the study highlights the importance of river discharge and atmospheric forcing in determining the hydrology and circulation in the Adriatic Sea.